QuickTime Q & A for QuickTime and Video Compression

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TOKYO (MacHouse) – We have posted a new article to comprehensively answer some of common questions concerning QuickTime and video compression. Most of the questions come from Apple Discussions > QuickTime.






Click on the button to read the article. VTC

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4 Responses to QuickTime Q & A for QuickTime and Video Compression

  1. John Laughton says:

    MacBook Pro
    2.4 G, IntelCore 2 Duo
    2GB Ram

    I recently got a JVC Everio Digital video camcorder. This produces .MOD files
    From blogs I read, this is basically a mpeg2 file
    I can use standard QT to pull the files in as .mov files
    Then I saw the QT mpeg-2 plugin, so I got it
    This can convert the mod file to a dv file

    I then used iDVD to make a dvd with the same source clip with 2 clips, one with the mov, the other the dv
    I did not see any real difference ?
    Is iDVD re-encoding and losing info ?

    Here is the stream info

    Stream: MOV005.MOD
    Path: ~/Movies/iDvd/MOV005.MOD
    Type: MPEG program stream

    Duration: 0:02:52
    Data Size: 136.39 MB
    Bit Rate: 6.63 Mbps

    Video Tracks:
    224 MPEG-2, 720 × 480, 16:9, 29.97 fps, 8.40 Mbps, upper field first

    Audio Tracks:
    128 AC3 2/0, 48 kHz, 384 kbps
    =============================
    Stream Files:
    MOV005.MOD (136.39 MB)

    Stream: clip-2007-09-22 07;04;00.mov
    Path: ~/Movies/iMovie Events.localized/Alex busc 22 Sept 2007/clip-2007-09-22 07;04;00.mov

    Duration: 0:02:52
    Data Size: 149.67 MB
    Bit Rate: 7.27 Mbps

    Video Tracks:
    ‘m2v1’, 720 × 480, 29.97 fps, 5.74 Mbps

    Audio Tracks:
    16-bit Little Endian mono, 48 kHz, 768 kbps

    Stream Files:
    clip-2007-09-22 07;04;00.mov (149.67 MB)
    ==================================
    Stream: MOV005.dv
    Path: ~/Movies/iDvd/MOV005.dv

    Duration: 0:02:52
    Data Size: 1.16 GB
    Bit Rate: 57.54 Mbps

    Video Tracks:
    DV/DVCPRO – NTSC, 720 × 480, 16:9, 29.97 fps, 28.77 Mbps

    Audio Tracks:
    DV stereo, 48 kHz, 28.77 Mbps

    Stream Files:
    MOV005.dv (1.16 GB)

  2. admin says:

    The DV compression leads to a large file mainly because it doesn’t use interframe compression. MPEG-2 compression uses both intraframe and interframe compression methods. If MPEG-2 or MPEG-4 used only intraframe compression, the file size would be fairly big. Anyhow, I don’t know how different the Video TS content with two different sources. Just because MPEG produces smaller files, that doesn’t necessarily mean that DV files have more information. MPEG uses temporal redundancy. That means when you play back an MPEG video, a near-complete frame will be restored with residual plus a reference frame.

  3. John Laughton says:

    Hi thanks for the feedback
    I am not that knowledgable on video compression
    I guess I am wondering what the $20 mpeg-2 plugin buys me ?
    I understand streamclip is very comprehensive, but in my application it seems like I don’t gain anything

  4. admin says:

    I suppose that you have benefited from having the MPEG-2 component because it has helped MPEG Streamclip demux your MOD file into audio and video streams and convert it into DV or MOV.

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